Discussion

Ross coined this descriptive name 'MTBS' because of the physical resemblance of these patients to the mascot of a French tire manufacturer.[2] It is a hamartomatous disorder involving either adipose tissue or smooth muscle in the deeper dermis of the skin.

The condition may be familial and there is evidence of autosomal dominant mode of inheritance affecting several members in successive generations of a family.[4] The pathogenesis is yet unclear; chromosomal anomalies detected in this condition are deletion of the short arm of chromosome 11[5] and paracentric inversion of the long arm of chromosome 7.[6] Multiple, asymptomatic, circumferential folds, simulating skin bands are the most prominent feature of MTBS. These are usually present since birth. Extremities are the commonest sites of involvement, others being the trunk, palms and soles. Hypertrichosis of the involved areas may be observed.[7],[8]

Multiple congenital anomalies have been described as associations. These include facial dysmorphism, as described in our patient, long and curled eyelashes, bushy eyebrows and bilateral epicanthic folds.[8] Low-set ears, cleft lip and palate, hypoplastic teeth and mandible may be present.[8] Other features include developmental delay, seizure disorders, pectus excavatum, congenital heart defect and undescended testis with abnormal histology.[3],[8],[9]

The cause of the dermatomegaly may be a diffuse lipomatous nevus involving the deeper dermis as reported in the first patient.[2] Hence the name 'congenital diffuse lipomatosis' has been attributed to this condition.[2],[8] Underlying smooth muscle hamartoma may be present[8] as seen in the index case. Scarring, instead of increased adipocytes or muscle fibers has been reported.[10] Sato et al .[11] have reported fragmentation of elastic fibers in addition to increased smooth muscle tissue in their patient and suggested that abnormal elastic fiber formation may be a pathogenetic factor in this condition.

The affected children are otherwise normal. The skin folds gradually diminish and disappear without any intervention.[8],[12] In familial cases, older family members may show few remnants of deep skin folds.

Congenital amniotic bands are usually solitary and present on limbs. These may be part of amniotic band sequence, present in association with multiple congenital anomalies. Beare-Stevenson cutis gyrata syndrome is associated with dermatomegaly which is localized to the scalp, forehead, face and neck.[13] Some authors believe that MTBS may not be a single disorder but a clinical finding associated with many other conditions.[13]

Circumferential skin creases have been included as a component of some recently described entities like HITCH syndrome (Hearing Impairment, undescended Testis, Circumferential skin creases and mental Handicap)[14] and multiple congenital anomalies and mental retardation (MCA/MR) syndrome.[15]

One patient of MTBS has been reported from India, who had mild affection and there was spontaneous involution of the skin creases during childhood.[12] Our patient has been kept under regular follow-up for the evaluation of course of the disease.